How can I test a custom DelegatingHandler in the ASP.NET MVC 4 Web API?

Question

I\'ve seen this question come up in a few places, and not seen any great answers. As I\'ve had to do this myself a few times, I thought I\'d post my solution. If you have an

Answer 1

I was just looking for the same thing but came up with a more concise approach that didn't use http client. I wanted a test to assert the message handler consumed a mocked logging component. I didn't really need the inner handler to function, just to "stub" it out to satisfy the unit test. Works for my purpose :)

//ARRANGE
        var logger = new Mock();
        var handler= new ServiceLoggingHandler(logger.Object);
        var request = ControllerContext.CreateHttpRequest(Guid.NewGuid(), "http://test",HttpMethod.Get);

        handler.InnerHandler = new Mock(MockBehavior.Loose).Object;

        request.Content = new ObjectContent(Company.CreateCompanyDTO(), new JsonMediaTypeFormatter());
        var invoker = new HttpMessageInvoker(handler);

        //ACT
        var result = invoker.SendAsync(request, new System.Threading.CancellationToken()).Result;

//ASSERT